High barrier properties against odorous materials are required for plastic films for packaging odorous wastes, such as colostomy bags and garbage bags, and plastic films for packaging fish, fruits, vegetables, and the like.
Single-layer films of low-density polyethylene, plasticized polyvinyl chloride and the like have been used for colostomy bags. However, single-layer films of low density polyethylene, plasticized polyvinyl chloride and the like, have insufficient odor barrier properties, and the odor of the contents emanates outward to cause the wearer to become uncomfortable. There is a need for a film having high odor barrier properties. The use of multilayered films comprising a barrier layer of ethylene-vinyl alcohol copolymer (hereinafter referred to as EVOH) or polyvinylidene chloride resin having odor barrier properties have been proposed. Japanese Utility Model Application Laid-open No. 175248/1985 discloses a colostomy bag comprising EVOH as a barrier layer. However, colostomy bags comprising EVOH as an odor barrier layer have not been put into practical use, because the barrier properties of EVOH against low-molecular weight amines such as ammonia are somewhat insufficient. The use of polyvinylidene resin has been disclosed, for example, in Japanese Patent Kohyo No. 501631/1982 and Japanese Patent Application Laid-open No. 137368/1985. However, commercially available colostomy bags utilizing polyvinylidene chloride are still unsatisfactory in odor barrier properties.
Japanese Patent Application Laid-open Nos. 60732/1986 and 148236/1986 disclose a plastic film containing a deodorant composed of a ferrous compound and an organic acid. Japanese Patent Application Laid-open No. 86031/1987 discloses a resin composition containing a deodorant of an organic acid, and Japanese Patent Application Laid-open Nos. 235363/1987, 235364/1987 and 235365/1987 disclose resin compositions containing deodorant composed of a zinc compound and an inorganic acid. However, the deodorizing function of deodorants has its limit and the odor of odorous materials cannot completely be barred. Further no combinations of gas barrier resin with deodorant are yet known.